Iraqi deputy premier Ahmed Chalabi has met senior officials in the US despite an ongoing investigation into whether he passed US secrets to Iran.

Mr Chalabi met Secretary of State Condoleezza Rice, Vice President Dick Cheney and Stephen Hadley, the president's national security adviser.

He will make his first speech in the US for two years later on Wednesday.

Some US politicians have questioned the apparent rehabilitation of a man once touted by the US as a future president.

Dick Durbin, the Democratic senator for Illinois, called the visit "something curious".

"It is very difficult to track how this man, who gave us such misleading information before the invasion of Iraq, now under active investigation for endangering American troops, is now the toast of the town," Sen Durbin said in a speech on Tuesday.

The US state department dismissed suggestions that they should not welcome Mr Chalabi because of his controversial past.

"Ahmed Chalabi is the deputy prime minister of Iraq; he is an official and a representative of the government of Iraq," said Adam Ereli, a state department spokesman.

Investigation 'still open'

Nevertheless, Mr Chalabi's relationship with the US has been strained since 2004.

As one of the Pentagon's main sources of intelligence on Iraq's alleged weapons programme under former Iraqi President Saddam Hussein, Mr Chalabi became sidelined when no evidence supporting his claims could be found.

Chalabi has formed a new coalition for the December election

He was also blamed for advising the Coalition Provisional Authority to dissolve the Iraqi army, a decision that many officials now regret.

An FBI investigation was launched last year after US intelligence officials alleged that Mr Chalabi or his aides had informed Iran that their message encryption codes had been cracked.

His home and offices were raided and an arrest warrant was issued for his security chief, Araz Habib.

Mr Chalabi has denied all the allegations, but the FBI told the Wall Street Journal this week that their investigation is still open.

New coalition

Mr Chalabi and his political party, the Iraqi National Congress, contested this January's parliamentary elections as a member of the Shia-led United Iraqi Alliance.

The UIA won a slim majority in the National Assembly and Mr Chalabi was appointed one of the two deputy premiers in Iraq's transitional government.

However, his party has split with the UIA for December's elections and formed the National Congress Coalition with other "liberal" parties and "moderate" political and religious figures.

His controversial career includes a conviction and 22-year jail sentence in Jordan for embezzlement following the collapse of his Petra Bank in 1989.

Mr Chalabi, who was tried in absentia, has always proclaimed his innocence and says the charges were political.